Public Enemy leader Chuck D has been most visible recently as a supporter of Napster's controversial MP3-trading software, but the rapper and online activist has long been pushing the digital envelope.

Last year, Chuck D was marketing his group's latest album, There's a Poison Goin' On, in a variety of new formats.

On June 4, 1999, downloadable sales of Poison in MP3 and Liquid Audio formats began at www.atomicpop.com. Public Enemy had primed fans for the release earlier in the year with free downloads of two of the album's tracks, "Swindler's Lust" and "Are You Gonna Go Our Way???"

The band also took the unique  and largely overlooked  step of releasing the album on 100 megabyte Iomega Zip disks, a format typically used for storing large computer files.

Most of the 100,000 copies of There's a Poison Goin' On sold online and in brick-and-mortar stores were traditional CDs, priced at $10. About 10 percent were sold as $8 downloads, according to Rich Holtzman, vice president of marketing at Atomic Pop. A few thousand copies were sold on double-disc vinyl, while cassette sales were negligible, Holtzman said.

All of the sales were boosted by the free song downloads, according Holtzman. "In the long run, if you have a great album, people are going to buy it," he said. "You shouldn't be afraid to give away one or two songs  even the single  because you know there are three, four, five or six great songs on there that people will want."

About 3,500 of the 5,000 Zip disk copies of the album, initially offered at the suggested retail price of $16.98, have been sold, said Holtzman, who now questions whether the offering was a wise one. Music retailers didn't know how to stock the Zip disks, he said, and most of them were sold to buyers who seemed to want them more for their value as souvenirs than as a new way to own an album.